A fire injured 12 people, including five seriously, as it burned through an apartment building in Harlem Monday night, the FDNY said.

The blaze took place on the 9th floor of multi-family apartment building on Nicholas Ave. at around 10:17 p.m., according to fire officials.

Six civilians and one firefighter suffered minor injuries.

Five people were seriously hurt.

The cause of the blaze was under investigation Tuesday morning.